I haven't read every last comment on this thread, but I have read most of them. It seems to me that there are two main points:
1) A Mac direction was announced and discussed somewhat openly, but now has been "disappeared" from the website
2) This is a big technical undertaking, so maybe this implies big problems or even abandonment of that direction.
I guess Alex has mostly cleared up both of these points. I would suggest, however, that the issues with a launch like this aren't only development-related. While I personally have absolutely zero interest in anything even remotely related to Apple, it should be clear to everybody that a move into this space is a huge marketing move for Gibson/Cakewalk. So one interpretation is that they have decided to scrub the preliminary information from public sources as they prepare for the real launch.
That would be a perfectly sensible thing to do, IMHO, and would also explain why information on this forum would be limited.
P.S. While I personally have no use for Apple, I do hope this initiative is successful because it has the potential to raise the prominence of SONAR in the DAW wars, and that should be good for the Windows users too.